Improved clipboard handling

Author: justanotheranonymoususer

fixlayouts.cpp

@@ -13,9 +13,15 @@ void ConvertSelectedTextInActiveWindow(HKL hklSource, HKL hklTarget)
 
 	// store previous clipboard data and set clipboard to dummy string
 	ClipboardData prevClipboardData;
-	StoreClipboardData(&prevClipboardData);
+	if(!StoreClipboardData(&prevClipboardData))
+		return;
 
-	SetClipboardText(dummy);
+	if(!SetClipboardText(dummy))
+	{
+		// restore the original clipboard data
+		RestoreClipboardData(&prevClipboardData);
+		return;
+	}
 
 	// copy the selected text by simulating Ctrl-C
 	SendKeyCombo(VK_CONTROL, 'C', FALSE);
@@ -74,7 +80,6 @@ void ConvertSelectedTextInActiveWindow(HKL hklSource, HKL hklTarget)
 
 	// restore the original clipboard data
 	RestoreClipboardData(&prevClipboardData);
-	FreeClipboardData(&prevClipboardData);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -194,97 +199,172 @@ HKL DetectLayoutFromString(const WCHAR* str, int* pmatches)
 // You must call FreeAllClipboardData on `formats` when it's no longer needed.
 BOOL StoreClipboardData(ClipboardData* formats)
 {
-	if(OpenClipboard(NULL))
+	if(!OpenClipboard(NULL))
+		return FALSE;
+
+	formats->count = CountClipboardFormats();
+	if(formats->count == 0)
+	{
+		DWORD dwError = GetLastError();
+		CloseClipboard();
+		return dwError == ERROR_SUCCESS;
+	}
+
+	formats->dataArray = (ClipboardFormat*)malloc(sizeof(ClipboardData) * formats->count);
+	ZeroMemory(formats->dataArray, sizeof(ClipboardData) * formats->count);
+	int i = 0;
+
+	UINT format = EnumClipboardFormats(0);
+	while(format)
 	{
-		formats->count = CountClipboardFormats();
-		formats->dataArray = (ClipboardFormat*)malloc(sizeof(ClipboardData) * formats->count);
-		ZeroMemory(formats->dataArray, sizeof(ClipboardData) * formats->count);
-		int i = 0;
-		UINT format = EnumClipboardFormats(0);
-		while(format)
+		if(i > formats->count - 1)
+			break;
+
+		HANDLE dataHandle = GetClipboardData(format);
+		if(!dataHandle)
+			break;
+
+		size_t size;
+		if(!(GlobalFlags(dataHandle) & GMEM_DISCARDED))
 		{
-			HANDLE dataHandle = GetClipboardData(format);
-			LPVOID source = GlobalLock(dataHandle);
-			size_t size = GlobalSize(dataHandle);
-			formats->dataArray[i].format = format;
-			formats->dataArray[i].dataHandle = GlobalAlloc(GHND, size);
-			LPVOID dest = GlobalLock(formats->dataArray[i].dataHandle);
-			CopyMemory(dest, source, size);
-			GlobalUnlock(formats->dataArray[i].dataHandle);
-			GlobalUnlock(dataHandle);
-
-			// next format
-			format = EnumClipboardFormats(format);
-			i++;
+			size = GlobalSize(dataHandle);
+			if(size == 0)
+				break;
 		}
-		CloseClipboard();
-		return TRUE;
+		else
+			size = 0;
+
+		LPVOID source = GlobalLock(dataHandle);
+		if(!source)
+			break;
+
+		BOOL bCopySucceeded = FALSE;
+
+		formats->dataArray[i].format = format;
+		formats->dataArray[i].dataHandle = GlobalAlloc(GHND, size);
+		if(formats->dataArray[i].dataHandle)
+		{
+			if(size == 0)
+			{
+				bCopySucceeded = TRUE;
+			}
+			else
+			{
+				LPVOID dest = GlobalLock(formats->dataArray[i].dataHandle);
+				if(dest)
+				{
+					CopyMemory(dest, source, size);
+					GlobalUnlock(formats->dataArray[i].dataHandle);
+					bCopySucceeded = TRUE;
+				}
+			}
+
+			if(!bCopySucceeded)
+				GlobalFree(formats->dataArray[i].dataHandle);
+		}
+
+		GlobalUnlock(dataHandle);
+
+		if(!bCopySucceeded)
+			break;
+
+		i++;
+
+		// next format
+		format = EnumClipboardFormats(format);
 	}
-	return FALSE;
-}
 
-///////////////////////////////////////////////////////////////////////////////
-// Restores the data in the clipboard from `formats` that was generated by
-// StoreClipboardData.
-BOOL RestoreClipboardData(const ClipboardData* formats)
-{
-	if(OpenClipboard(NULL))
+	CloseClipboard();
+
+	if(format) // if failed before completion
 	{
-		EmptyClipboard();
-		for(int i = 0; i < formats->count; i++)
+		for(int j = 0; j < i; j++)
 		{
-			SetClipboardData(formats->dataArray[i].format, formats->dataArray[i].dataHandle);
+			GlobalFree(formats->dataArray[j].dataHandle);
 		}
-		CloseClipboard();
-		return TRUE;
+
+		free(formats->dataArray);
+		return FALSE;
 	}
-	return FALSE;
+
+	return TRUE;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
-// Frees `formats` allocated by StoreClipboardData
-void FreeClipboardData(ClipboardData* formats)
+// Restores the data in the clipboard from `formats` that was generated by
+// StoreClipboardData, and frees allocated data.
+BOOL RestoreClipboardData(ClipboardData* formats)
 {
+	if(!OpenClipboard(NULL))
+		return FALSE;
+
+	EmptyClipboard();
+	for(int i = 0; i < formats->count; i++)
+	{
+		SetClipboardData(formats->dataArray[i].format, formats->dataArray[i].dataHandle);
+	}
+
+	CloseClipboard();
 	free(formats->dataArray);
+	return TRUE;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 // Gets unicode text from the clipboard. 
 // You must free the returned string when you don't need it anymore.
 WCHAR* GetClipboardText()
 {
+	if(!OpenClipboard(NULL))
+		return FALSE;
+
 	WCHAR* text = NULL;
-	if(OpenClipboard(NULL))
+	HANDLE handle = GetClipboardData(CF_UNICODETEXT);
+	if(handle)
 	{
-		HANDLE handle = GetClipboardData(CF_UNICODETEXT);
 		WCHAR* clipboardText = (WCHAR*)GlobalLock(handle);
-		if(!clipboardText) return NULL;
-		size_t size = sizeof(WCHAR) * (wcslen(clipboardText) + 1);
-		text = (WCHAR*)malloc(size);
-		if(!text) return NULL;
-		memcpy(text, clipboardText, size);
-		CloseClipboard();
+		if(clipboardText)
+		{
+			size_t size = sizeof(WCHAR) * (wcslen(clipboardText) + 1);
+			text = (WCHAR*)malloc(size);
+			if(text)
+				memcpy(text, clipboardText, size);
+
+			GlobalUnlock(handle);
+		}
 	}
+
+	CloseClipboard();
 	return text;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 // Puts unicode text on the clipboard
 BOOL SetClipboardText(const WCHAR* text)
 {
-	if(OpenClipboard(NULL))
+	if(!OpenClipboard(NULL))
+		return FALSE;
+
+	BOOL bSucceeded = FALSE;
+
+	size_t size = sizeof(WCHAR) * (wcslen(text) + 1);
+	HANDLE handle = GlobalAlloc(GHND, size);
+	if(handle)
 	{
-		size_t size = sizeof(WCHAR) * (wcslen(text) + 1);
-		HANDLE handle = GlobalAlloc(GHND, size);
 		WCHAR* clipboardText = (WCHAR*)GlobalLock(handle);
-		memcpy(clipboardText, text, size);
-		GlobalUnlock(handle);
-		EmptyClipboard();
-		SetClipboardData(CF_UNICODETEXT, handle);
-		CloseClipboard();
-		return TRUE;
+		if(clipboardText)
+		{
+			memcpy(clipboardText, text, size);
+			GlobalUnlock(handle);
+			bSucceeded = EmptyClipboard() &&
+				SetClipboardData(CF_UNICODETEXT, handle);
+		}
+
+		if(!bSucceeded)
+			GlobalFree(handle);
 	}
-	return FALSE;
+
+	CloseClipboard();
+	return bSucceeded;
 }
 
 ///////////////////////////////////////////////////////////////////////////////

fixlayouts.h

@@ -28,8 +28,7 @@ HKL DetectLayoutFromString(const WCHAR* str, BOOL* pmatches);
 
 // Functions to store and restore all of the data in the clipboard
 BOOL StoreClipboardData(ClipboardData* formats);
-BOOL RestoreClipboardData(const ClipboardData* formats);
-void FreeClipboardData(ClipboardData* formats);
+BOOL RestoreClipboardData(ClipboardData* formats);
 
 // Convenience functions for the clipboard
 WCHAR* GetClipboardText();